This present invention relates to machine tool accessories and more specifically to a T-slot accessory work holder specifically for milling machines. The construction of typical milling machines (specifically the types used in metal fabrication shops and machine shops) provides a long planar table to hold a work piece below a milling spindle.
A milling machine table is a large planar surface on which metal blocks are attached permitting metal removal from work pieces held on the milling machine table surface. Drilling, boring, metal profiling and various other metal removal tasks are performed thereon. The machine table is generally rectangular in shape, although special tables may be fabricated that are round or square. One obvious feature of the machine table is a very simple feature, T-Slots. The T-Slots are specially shaped channels that run along the length of the machine table. The T-Slots affords the machinist user with the limited ability to attach vises and other work holding devises. Special work holding tools such as T-Nuts, Step Blocks, and Threaded Rods are used to securely clamp the work piece and attaching device to the planar surface.
T-Slots have long been found in machine tool assemblies. No known multiple T-slot assembly permitting a variety of positions to be formed for clamping or holding a work piece on a milling machine table and for which no preparatory mounting of affixing hardware is required are known to applicant. For a recent description of the state of this art, see U.S. Pat. No. 6,158,728 to Smith, issued Dec. 12, 2000.
Most machine tables have three or four T-Slots in them. T-Slots are even more useful on the larger machine tables. The T-Slots incorporated in existing machine tables are fixed and unmovable, and typically run in only one direction, thereby limiting the work holding strategy. There is a plethora of vises, predrilled fixing plates, angle plates, and also various clamps, tightening screws, nuts, bolts, springs, pins, and even pallets that mimic the basic features of the machine table, and these pallets can be typically changed out, but require preparatory mounting hardware to mount to the machine table and also require time and energy to unbolt, remove and rearrange the work piece for additional desired work. In order to accommodate the wide variety of milling jobs that a shop may be asked to perform, the machine shop retains an inventory of numerous expensive clamps and various other work holding equipment. For instance using modular fixing plates and the necessary clamps, riser blocks and various assortments of screws, nuts, and positioning blocks are very expensive. Setup time for attaching these fixing plates to the planar surface can be quite lengthy thereby resulting in lost time for actual machining operations, and consequent loss of revenue.
A new accessory has been invented to afford the machine shop more options in work holding. This new device is designed to mount directly on the milling machine table without the need for any sort of preparatory devices or hardware. This new accessory is called a T-Slot Block. The T-Slot Block features a T-Slot, just like the milling machine's table, and it also has tabs that extend outward from the base of the T-Slot Block. These tabs are called keys. These tabs or keys are designed to mount the T-Slot Block quickly and accurately in the machine table's T-Slot.
The T-slots in the T-Slot Block run perpendicular to the direction of the tabs or keys. Thus the T-slots in the T-Slot Block run perpendicular to the milling machine's T-slots.
The T-Slot Block is manufactured from a single piece of aluminum, or steel. Other materials, well known to those designing and constructing machine tool accessories may be substituted without departing from the spirit or intent of this application. Secondary machining operations can be performed on the T-Slot Blocks such as precision grinding, and heat hardening, depending on the precision of measure a customer might require. Manufacturing the T-Slot Block out of aluminum allows the customer an inexpensive unit, and it also allows the customer to perform specialized fixing since the T-Slot Block can be cut to conform to odd or unusual shape for parts that must be held. The T-Slot Block can be offered in various lengths, widths, and heights. The T-Slot Block can be fabricated with many predrilled and tapped holes or, alternatively, with no drilled and tapped holes. Furthermore, the T-Slot Block can have one or more tabs on the base of the T-Slot Block or anywhere on the T-Slot Block. The T-Slot Block can additionally provide removable tabs to allow total flexibility in the use of the T-Slot Block. Additionally multiple T-Slots can be offered, on the top, or sides, of the T-Slot Block and some T-Slots may be perpendicular or parallel or both on the T-Slot Block body. The general shape of the T-Slot Block is rectangular or cubical in appearance, but some can be triangular or angular or round. Furthermore, a custom T-Slot Block can be offered in which a T-Slot has been left off of the block, so that a customer can mill his T-Slot at a location on the block that accomplishes a job required by the machinist or the machinist can mill custom shapes to fit the profile of the part.